Lecture 25

Lecture 25 - How the Gulf of California Formed Stage 1:...

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Unformatted text preview: How the Gulf of California Formed Stage 1: Stage Subduction along west coast, followed by coastal transform fault fault Stage 2: Stage Transform and spreading centers jump in jump 10.07.a Observe how smaller seas near Eurasia formed North Sea: Continental rifting during formation of Atlantic Persian Gulf: Persian Loading by thrust sheets during collision during Red Sea: Rifting then Red early stages of seafloor spreading seafloor 10.08.a Observe where coral reefs form Barrier reef Car bon ate pla tfor m 10.09.a Fringing reef Fringing Great Barrier Reef Atoll Observe one way an atoll forms 10.09.b1-3 Volcanic island Volcanic forms, followed by formation of fringing reef fringing Island cools Island and sinks but reef continues to build upward toward light toward Volcano sinks Volcano below sea level, leaving reef as atoll reef Observe the location of reefs around the world Florida and Florida Bahamas Bahamas Hawaii Yucatan Lesser Lesser Antilles Antilles Red Sea Indonesia Philippines East East Africa Africa Polynesia Micronesia Indian Indian Ocean Ocean Great Barrier Great Reef Reef 10.09.c1 Observe the Observe features and structures of continental margins margins 10.10.a Continental Continental shelf shelf Submarine Submarine canyon canyon Continental Continental slope slope Continental Continental rise rise Sediment Sediment Thick Thick sediment sediment Normal Normal faults faults Continental Continental slope slope Abyssal Abyssal plain plain Underwater Slope Failures Turbidity current Graded beds 10.10.c Deposition in Deposition submarine fans submarine Underwater Underwater landslides on continental slope and flanks of islands islands Submarine Canyons Turbidity currents erode into Turbidity continental slope continental 10.10.c River and turbidity River currents eroded into continental shelf continental Observe some settings that can deposit salt Observe Broad flat areas Broad adjacent to sea adjacent Bodies of water Bodies with evaporation with Behind barrier that Behind restricts influx of seawater seawater 10.11.a1 What Structures Do Salt Deposits Form? Salt Domes 10.11.c Faulting and Faulting folding over weak salt layer layer Observe the setting of salt structures along the Gulf Observe Coast of the United States. Salt is shown in black. Coast Thick layer of salt deposited Thick during evaporation of seawater during Subsurface flow of Subsurface salt disrupts surface salt Pressure of overlying Pressure rocks causes salt to flow up and sideways flow 10.11.d1 200 m.y. Ago: End of Pangaea Central Atlantic forms Central as NAM-Africa rift as One global One ocean ocean Te thy sS ea Gondwana Gondwana intact intact 10.12.a1 150 m.y. Ago: New Oceans Open Central Central Atlantic open open Gondwana Gondwana starts rifting starts 10.12.a2 120 m.y. Ago: Dispersal of Gondwana NAM – Europe still joined Southern Southern continents mostly outlined outlined 10.12.a3 90 m.y. Ago: Atlantic Ocean Open NAM rifts from NAM Europe, forming North Atlantic North Gondwana Gondwana continents isolated continents 10.12.a4 30 m.y. Ago: Closing Tethys Sea Tethys nearly Tethys closed closed India collides Asia 10.12.a5 Present Day 10.12.a6 Predict what will happen in the future to each ocean Observe the present setting of the Gulf of Mexico Observe and the Caribbean region and Subduction Subduction beneath Central Am. Central Transform Subduction Subduction beneath Lesser Antilles Lesser Complex area 10.13.a1 Jurassic History (175 m.y. to 130 m.y. ago) Early rifting 10.13.a Gulf Gulf opens opens Gulf stops Gulf growing growing Cretaceous to Neogene History (84 to 5 m.y. ago) Plateau Plateau enters Caribbean Caribbean 10.13.a Cuban Cuban collision collision Panama Panama connection connection Investigation: How Did These Ocean Features and Investigation: Continental Margins Form? Continental 10.14.a1 Location of Cross Section Location of Location cross section cross A' 10.14.a A ...
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This note was uploaded on 01/24/2011 for the course GEOL 100 taught by Professor Martin during the Fall '08 term at Maryland.

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